fix: 商业认证图标逻辑反转 — 认证用户点亮，未认证灰色

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/views/UserManagement.vue

@@ -100,8 +100,8 @@
             <option value="editor">编辑</option>
             <option value="senior_editor">高级编辑</option>
           </select>
-          <button v-if="!u.business_verified" class="btn-sm btn-outline" @click="grantBusiness(u)" title="开通商业认证">💼</button>
-          <button v-else class="btn-sm btn-outline" @click="revokeBusiness(u)" title="撤销商业认证" style="opacity:0.5">💼✕</button>
+          <button v-if="u.business_verified" class="btn-sm btn-outline" @click="revokeBusiness(u)" title="撤销商业认证">💼</button>
+          <button v-else class="btn-sm btn-outline" @click="grantBusiness(u)" title="开通商业认证" style="opacity:0.3">💼</button>
           <button class="btn-sm btn-delete" @click="removeUser(u)" title="删除用户">🗑️</button>
         </div>
       </div>